Help! Getting Error “Invalid Use of Null”

I have created an application in which I needed to do queries on excel sheets uploaded by various users of the site. Users can perform any operation like Insert, Update, Delete etc. with this application well in any manner but sometimes when I am updating my excel sheets it displays and error like “Invalid Use of Null”. Have you ever faced this type of error before? How to solve it? Please help me to solve it.

Well it's difficult to say exactly why, especially without seeing the code...

There are plenty of reasons for "Invalid use of Null" including..::

String manipulation functions, require a String (Substring, Len, etc....) passing Null values to them will throw an error..

Assigning a Null value for any other Data Type other than Variant..

Math on nulls ie..:: Totals = seq1 + text2 + string3 ...(where one of them is a number stored in string)..

Opening a null pointer file..:: Open (filename) .where filename is null...

start checking for some of these conditions, and add null checking, to skip over...